Catheter and catheter assembly

ABSTRACT

A treatment method is disclosed, which includes preparing a catheter assembly by inserting an inner catheter into an outer catheter and screwing a protrusion of the outer catheter into a helical groove of the inner catheter; introducing the catheter assembly into the radial artery along a guide wire; pushing the catheter assembly along the guide wire to a target site in front of a stenosis of a blood vessel; releasing the screwing between the helical groove of the inner catheter and the protrusion of the outer catheter after a distal end of the catheter assembly reaches the target site; and causing the outer catheter to abut on at least a part of wall surfaces of a thoracic aorta and an abdominal aorta while drawing a helix and causing the treatment device to protrude from a distal end of the outer catheter at the stenosis.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 16/135,184 filed on Sep. 19, 2018, which claims priority toJapanese Application No. 2017-181455 filed on Sep. 21, 2017, the entirecontent of both of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure generally relates to a catheter and a catheterassembly.

RELATED ART

In recent years, a technique known as Trans Radial Intervention (TRI),which can perform a treatment by introducing a catheter from an artery(a radial artery or a brachial artery) of an arm has attracted attentionsince a physical burden on a patient is relatively small and the patientcan be discharge from the hospital sooner.

For example, JP 2014-230710 A describes a technique that performstreatment by introducing a catheter from an artery of an arm anddelivering the elongated catheter to a lesion of, for example,peripheral arterial disease (PAD) formed in a blood vessel of a lowerlimb.

As described in JP 2014-230710 A, the catheter delivered to the lesionin a blood vessel of a lower limb via the artery of the arm has arelatively long length in the longitudinal direction. When handling sucha catheter having the relatively long length in the longitudinaldirection, a surgeon takes a measure by winding the catheter andbundling the catheter with a clip or the like in order to prevent thecatheter from being in contact with an unclean surface such as a floor,for example. In this manner, the surgeon needs to pay attention suchthat the catheter is not brought into contact with an unclean surfacewhen using a catheter whose length in the longitudinal direction isrelatively long.

SUMMARY

A catheter and a catheter assembly are disclosed, which are relativelyeasy to handle.

A catheter is disclosed, which includes: an elongated shaft configuredto be inserted into a body lumen; and a hub connected to a proximal endside of the shaft. The shaft forms a first shape at least a part ofwhich is wound in a state where the shaft is suspended in a gravitydirection by holding the hub, and forms a second shape at least a partof which is wound and in which a length of the shaft along the gravitydirection is shorter than a length of the shaft along the gravitydirection in the first shape in a state where the hub and the shaft areplaced on a flat reference plane perpendicular to the gravity direction.

A catheter assembly is disclosed having an outer catheter and an innercatheter insertable into the outer catheter, each of the outer catheterand the inner catheter including an elongated shaft and a hub connectedto a proximal end side of the shaft. The shaft of at least one catheterof the outer catheter and the inner catheter forms a first shape atleast a part of which is wound in a state where the shaft is suspendedin a gravity direction by holding the hub of the one catheter, and formsa third shape in which at least a part of the shafts of the outercatheter and the inner catheter is wound in a state where the innercatheter is inserted into the outer catheter, the shafts of the outercatheter and the inner catheter are suspended in the gravity directionby holding the hub of the outer catheter or the inner catheter.

According to the catheter configured as described above, when a surgeonholds and manipulates a proximal end side of the catheter, at least apart of the shaft is wound to form the first shape and becomes compact.Thus, a risk of the catheter being in contact with an unclean surfacesuch as a floor can be reduced, and it becomes unnecessary or easier forthe surgeon to perform work of bundling the catheter with a clip or thelike so as to prevent the contact with the unclean surface, for example,such as the floor. In addition, when the surgeon places the catheter ona medical tray, a table, or the like, at least a part of the shaft formsthe second shape and becomes more compact than in the suspended state.In this manner, it is possible to provide a catheter which is relativelyeasy to handle.

According to the catheter assembly configured as described above, when asurgeon holds and manipulates a proximal end side of the catheterassembly in a state where the inner catheter is inserted into the outercatheter, at least a part of the shaft of the catheter assembly is woundto form the third shape and becomes relatively compact. Thus, a risk ofthe catheter assembly being in contact with an unclean surface such as afloor can be reduced, and it becomes unnecessary or relatively easy forthe surgeon to perform work of bundling the catheter with a clip or thelike so as to help prevent contact with an unclean surface such as thefloor. In this manner, it is possible to provide the catheter assemblywhich is relatively easy to handle.

In accordance with an aspect, a catheter is disclosed comprising: anelongated shaft to be inserted into a body lumen; a hub connected to aproximal end side of the shaft, wherein the shaft forms a first shape atleast a part of which is wound in a state where the shaft is suspendedin a gravity direction by holding the hub; a portion, which is a half ormore of the shaft from a distal end of the shaft to a distal end of thehub forms the first shape in the state where the shaft is suspended; anda hydrophilic coating layer is provided on at least a part of the distalend of the shaft such that a coating length of the hydrophilic coatinglayer is equal to or longer than 1/10 and equal to or smaller than ⅓ ofa length from the distal end of the shaft to the distal end of the hubin a straight state.

In accordance with another aspect, a treatment method is disclosedcomprising: preparing a catheter assembly by inserting an inner catheterinto an outer catheter and screwing a protrusion of the outer catheterinto a helical groove of the inner catheter; inserting a guide wire intoa lumen of the inner catheter of the catheter assembly such that theguide wire protrudes from a distal end of the inner catheter; insertingthe catheter assembly into an introducer sheath, the introducer sheathwhich pierces through and remains in a radial artery of a living body,in a state where the guide wire is inserted into a lumen of the catheterassembly; introducing the catheter assembly into the radial artery alongthe guide wire; pushing the catheter assembly to proceed along the guidewire to a target site in front of a stenosis of a blood vessel;releasing the screwing between the helical groove of the inner catheterand the protrusion of the outer catheter after a distal end of thecatheter assembly reaches the target site; removing the inner catheterfrom the living body while leaving the outer catheter and the guide wirein the blood vessel; inserting a treatment device along the guide wireinto a lumen of the outer catheter; and causing the outer catheter toabut on at least a part of wall surfaces of a thoracic aorta and anabdominal aorta while drawing a helix and causing the treatment deviceto protrude from a distal end of the outer catheter such that anexpanded portion is arranged at the stenosis.

In accordance with a further aspect, a treatment method is disclosedcomprising: inserting an inner catheter into an outer catheter andscrewing a protrusion of the outer catheter into a helical groove of theinner catheter to form a catheter assembly; inserting a guide wire intoa lumen of the inner catheter and protruding the guide wire from adistal end of the inner catheter; puncturing a radial artery of a livingbody with an introducer sheath; inserting a guide wire into a lumen ofthe catheter assembly; introducing the catheter assembly along with theguide wire into the radial artery via the introducer sheath; pushing thecatheter assembly along the guide wire to a target site in a bloodvessel; releasing the screwing between the helical groove of the innercatheter and the protrusion of the outer catheter after a distal end ofthe catheter assembly reaches the target site; removing the innercatheter from the living body while leaving the outer catheter and theguide wire in the blood vessel; inserting a treatment device along theguide wire into a lumen of the outer catheter; and causing the outercatheter to abut on at least a part of wall surfaces of a thoracic aortaand an abdominal aorta while drawing a helix and causing the treatmentdevice to protrude from a distal end of the outer catheter at the targetsite.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view illustrating a state where a catheterassembly stretched according to an embodiment of the disclosure.

FIG. 2 is an enlarged cross-sectional view in a longitudinal directionof the catheter assembly according to the embodiment.

FIG. 3A is a view illustrating a state where an inner catheter providedin the catheter assembly according to the embodiment is suspended.

FIG. 3B is a view illustrating a state where the catheter assemblyaccording to the embodiment is assembled and suspended.

FIG. 4A is a view illustrating a state where the inner catheteraccording to the embodiment is placed on a reference plane.

FIG. 4B is a view illustrating a state where the catheter assemblyaccording to the embodiment is assembled and placed on the referenceplane.

FIG. 5 is a cross-sectional view taken along a line V-V of FIG. 4A.

FIG. 6 is a schematic view for describing a technique using the catheterassembly according to the embodiment.

FIG. 7 is a view illustrating a state where an inner catheter accordingto a modified example is placed on a reference plane.

DETAILED DESCRIPTION

Hereinafter, a catheter and a catheter assembly according to embodimentsof the disclosure will be described with reference to the accompanyingdrawings. Incidentally, the following description does not limit thetechnical scope or the meaning of terms described in the claims. Inaddition, dimensional ratios of the drawings are exaggerated for theconvenience of description and may differ from actual ratios in somecases.

FIG. 1 is a view for describing the entire configuration of a catheterassembly 10 according to an embodiment. FIG. 2 is a view for describingeach part of the catheter assembly 10. FIGS. 3A to 5 are views fordescribing shapes of an inner catheter 200 and the catheter assembly 10.FIG. 6 is a view for describing a use example of the catheter assembly10.

The catheter assembly 10 is configured as a medical instrument(so-called guiding catheter) which is introduced into a blood vessel ofa patient in advance in order to guide a medical instrument (forexample, an image diagnostic catheter, a balloon catheter, or the like)for diagnosis and treatment to a lesion formed in the blood vessel of alower limb via an artery of an arm of a patient.

As briefly described with reference to FIG. 1, the catheter assembly 10includes an outer catheter 100 and an inner catheter 200 that isinserted into the outer catheter 100. Hereinafter, each part of thecatheter assembly 10 will be described.

In the description of the present specification, a direction in whichthe outer catheter 100 extends when the outer catheter 100 is straightlystretched will be referred to as a “longitudinal direction Y1” asillustrated in FIG. 1. In addition, a direction in which the innercatheter 200 extends when the inner catheter 200 is straightly stretchedwill be referred to as a “longitudinal direction Y2”. In addition, inthe longitudinal directions Y1 and Y2 of the respective catheters 100and 200, a side that is inserted into a body will be referred to as a“distal end side”, a side opposite to the distal end side and on whichthe operation at hand is performed will be referred to as a “proximalend side”. In addition, in each of the catheters 100 and 200, a distalend (most distal end) and the vicinity of the distal end (or most distalend) will be referred to as a “distal end portion”, and a proximal end(most proximal end) and the vicinity of the proximal end (or mostproximal end) will be referred to as a “proximal end portion”.

Outer Catheter

The outer catheter 100 includes an elongated outer shaft 110 that isinsertable into a blood vessel of a patient (corresponding to a “bodylumen”) and a hub 120 fixed to the proximal end portion of the outershaft 110 and configured to be held and operated by a surgeon.Hereinafter, each part of the outer catheter 100 will be described.

First, the outer shaft 110 will be described.

The outer shaft 110 has a tubular member having flexibility (i.e.,flexible tubular member). The outer shaft 110 has a lumen 110 a formedover the entire length of the outer shaft 110. When the surgeon insertsthe catheter assembly 10 into the blood vessel of the patient, the innercatheter 200 is inserted into the outer catheter 100 and a guide wire GWis inserted into the inner catheter 200 as illustrated in FIG. 6. Afterdelivering the catheter assembly 10 to a target site so as to be guidedby the preceding guide wire GW, the surgeon pulls the inner catheter 200out of the living body (i.e., removes the inner catheter from the livingbody) and inserts a medical instrument for diagnosis and treatment (forexample, an image diagnostic catheter, a balloon catheter, or the like)into the outer catheter to diagnose and treat the lesion. As describedabove, the inner catheter 200, the guide wire GW, the medical instrumentfor diagnosis and treatment, and the like can be inserted into the lumen110 a.

In the present embodiment, the outer shaft 110 has a tubular inner layer111, a reinforcing member 112 provided on an outer circumferentialsurface of the inner layer 111, and an outer layer 113 covering (i.e.,surrounding) the inner layer 111 and the reinforcing member 112 asillustrated in FIG. 2.

The material of the inner layer 111 can be a resin, for example, afluorine-containing ethylenic polymer such as PTFE(polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinylether copolymer), FEP (tetrafluoroethylene-hexafluoropropylenecopolymer), and ETFE (ethylene-tetrafluoroethylene copolymer), polyamidesuch as nylon, or a polyamide elastomer such as a nylon elastomer. Amongthe above-described resins, it is preferable to use PTFE or PFA having alow frictional resistance as the material of the inner layer 111. As theinner layer 111 is made of such a material (i.e., PTFE or PFA having alow frictional resistance), a frictional resistance of an innercircumferential surface of the outer shaft 110 can be reduced, and thesurgeon can smoothly move the medical instrument for diagnosis andtreatment that has been inserted into the lumen 110 a in thelongitudinal direction Y1.

In the present embodiment, the reinforcing member 112 can be a pluralityof strands (braid) braided in a mesh shape. The reinforcing member 112can be provided (i.e., arranged) over the entire part of the outer shaft110 excluding the distal end portion of the outer shaft 110. In thismanner, the outer shaft 110 has the reinforcing member 112, and thus,has a relatively high kink resistance, a relatively hightorque-transmitting property, and relatively high pushability.

The strand material of the reinforcing member 112 is not particularlylimited, for example, a metal strand, a resin strand, a combination ofthe metal strand and the resin strand, or the like can be used. Themetal strand material is not particularly limited, for example,stainless steel, tungsten, copper, nickel, titanium, a cobalt-chromiumalloy, a nickel-titanium alloy (a super-elastic alloy), a copper-zincalloy, an amorphous alloy, or the like can be used. The resin strandmaterial is not particularly limited, for example, a hard polymer suchas polyolefin, a liquid crystal polymer, or the like can be used. Asectional shape of the strand is not particularly limited, but can beformed in, for example, a substantially circular shape or asubstantially rectangular shape. Meanwhile, it is preferable that thesectional shape of the strand be a substantially rectangular shape sincethe operability can be improved by increasing the density of thereinforcing member 112 on the outer shaft 110. In accordance with anexemplary embodiment, the reinforcing member 112 may be configured usinga coil instead of braid.

The outer layer material 113 is not particularly limited, for example, apolymer material such as polyolefin (for example, polyethylene,polypropylene, polybutene, an ethylene-propylene copolymer, anethylene-vinyl acetate copolymer, an ionomer, or a mixture of two ormore kinds of these), polyvinyl chloride, polyamide, polyester, apolyester elastomer, a polyamide elastomer, polyurethane, a polyurethaneelastomer, polyimide, fluorine resin, or a mixture of the materials canbe used. Incidentally, the outer layer 113 may have a multilayerstructure in which different resin materials are stacked or a segmentstructure in which different resin materials are continuously joined. Inaddition, the outer layer 113 may have a hydrophilic coating layer on anouter surface of the outer layer 113.

A length L1 of the outer shaft 110 from a distal end of the outer shaft110 to a distal end of the hub 120 in the straight state (hereinaftersimply referred to as the “length L1 of the outer shaft 110”, seeFIG. 1) is preferably 1200 mm to 2500 mm, and more preferably 1500 mm to2000 mm such that the distal end of the outer shaft 110, which has beeninserted from the artery of the arm, reaches the blood vessel of thelower limb.

In accordance with an exemplary embodiment, the length of the outershaft 110 may be appropriately determined according to the size of thehuman body. In introducing from the radial artery, it is more preferablethat the length of the outer shaft 110 is 1200 mm to 1400 mm in order toreach the iliac artery. In order to reach the superficial femoral arteryfrom the radial artery, the length of the outer shaft 110 is preferably1400 mm to 1600 mm, and the length of the outer shaft is preferably 1600mm to 1800 mm for reaching the popliteal artery from the radial artery.

The outer shaft 110 can be evaluated with a three-point bending value.Here, the three-point bending refers to the maximum load when immersedin water at 37° C. for 30 minutes and then pushed with a support base ofR=2 mm and a pusher with a distance between the support stand of 25.4 mmand a test speed of 5 mm/min.

When the outer diameter of the outer shaft 110 is, the three-pointbending value is preferably 50 gf (gram-force) to 800 gf. If thethree-point bending value is 50 gf or less, the outer shaft 110 hangsdown and does not form a spiral. When the three-point bending value ofthe outer shaft 110 exceeds 800 gf, the outer shaft 110 is in a rolledstate, so it does not become a three-dimensional helical structure. Inthe case where the outer shaft 110 is a single body, if outer diameteris 2.5 mm and inner diameter is 2.2 mm, the three-point bending value is300 gf to 700 gf, the three-dimensional helical structure is obtained asa single body. In accordance with an embodiment, the three-point bendingvalue of the outer shaft 110 may be determined by a flexural modulusmeasured by the same method, and the three-point bending value ispreferably temporarily 110 MPa (mega pascal) to 260 MPa.

On the other hand, when the outer shaft 110 is used by inserting theinner shaft 210 of the dilator having the three-dimensional spiral shapeor the inner catheter 200 into the lumen of the outer shaft 110, thedilator and the inner shaft 210 form a three-dimensional spiral shape,three-dimensional helical structure is not obtained as a single body.The three-point bending value is preferably 50 gf or more and 200 gf orless. In accordance with an embodiment, the three-point bending value ofthe outer shaft 110 may be determined by a flexural modulus measured bythe same method, and the three-point bending value is preferably 30 MPa(mega pascal) to 300 MPa.

In accordance with an exemplary embodiment, the bending moment (M), forexample, of the outer shaft 110, can be calculated as follows:

M=FL/4=EI

I=π(D ⁴ −d ⁴)/64

where:

M=Bending moment;

I=Sectional moment of inertia of area;

E=Apparent flexural modulus;

D=Outer diameter (mm);

d=Inner diameter (mm);

L=Distance between fulcrums (mm);

F (N)=Load;

F is the load when the catheter is deflected by pushing the pusher by 1mm; and

1000 gf=9.8 N.

In addition, the outer shaft 110 may have a marker (not illustrated)having X-ray contrast property at a distal end portion of the outershaft 110.

Next, the hub 120 will be described.

The hub 120 includes: a hollow outer hub body portion 121 to which theouter shaft 110 is fixed; a strain relief 122 which covers a connectingportion between the outer shaft 110 and the outer hub body portion 121and suppresses generation of kinking of the outer shaft 110 at theconnecting portion; a plurality (two in the present embodiment) of wings123 protruding radially outward from an outer circumferential surface ofthe outer hub body portion 121; and a protrusion 124 provided at aproximal end portion of the outer hub body portion 121 and protrudingradially outward from the outer circumferential surface of the outer hubbody portion 121.

The outer hub body portion 121 has a lumen 121 a formed over the entirelength of the outer hub body portion 121. The lumen 121 a communicateswith the lumen 110 a of the outer shaft 110. The protrusion 124 can bescrewed into a helical groove 222 of the hub 220 of the inner catheter200 to be described later. When inserting the catheter assembly 10 intothe body, the surgeon inserts the inner catheter 200 into the outercatheter 100 and rotates the hub 120 of the outer catheter 100 withrespect to the hub 220 of the inner catheter 200. As a result, theprotrusion 124 is screwed into the helical groove 222, and the innercatheter 200 is fixed to the outer catheter 100.

The hub 120 material is not particularly limited, for example, variousthermoplastic elastomers such as a styrene type, a polyolefin type, apolyurethane type, a polyester type, a polyamide type, a polybutadienetype, a trans polyisoprene type, a fluorine rubber type, a chlorinatedpolyethylene type, and a combination of two or more kinds of these (apolymer alloy, a polymer blend, a multilayer body, or the like) can beused.

Inner Catheter

The inner catheter 200 includes an elongated inner shaft 210 and a hub220 that is fixed to a proximal end portion of the inner shaft 210 andconfigured to be held and operated by the surgeon. Hereinafter, eachpart of the inner catheter 200 will be described.

First, the inner shaft 210 will be described.

The inner shaft 210 includes a tubular member having flexibility (i.e.,flexible tubular member). The inner shaft 210 has a lumen 210 a formedover the entire length. As illustrated in FIG. 2, a guide wire GW can beinserted into the lumen 210 a.

The inner shaft 210 has a length L1 from the distal end of the innershaft 210 to the distal end of the hub 220 in a straight state(hereinafter simply referred to as “length L1”) from the distal end ofthe inner shaft 210 in a straight state so that the distal end of theinner shaft 110 inserted from the artery of the arm reaches the bloodvessel of the lower limb. Referred to as “the length L2 of the innershaft 210”, see FIG. 1), the length L2 of the inner shaft 210 ispreferably, for example, 1300 mm to 2600 mm, and more preferably 1600 mmto 2100 mm.

The inner shaft 210 may be appropriately determined according to thesize of the human body, but in the case of introduction from the radialartery, the length L2 of the inner shaft 210 is preferably, for example,1300 mm to 1500 mm to reach the iliac artery, from 1500 mm to 1700 mm toreach the superficial femoral artery, and from 1700 mm to 1900 mm toreach the popliteal artery.

The inner shaft 210 can be evaluated with a three-point bending value inthe same way as the outer shaft 110. When the outer diameter of theinner shaft 210 is 2.1 mm and the inner diameter is 1.1 mm, thethree-point bending value of the inner shaft 210 is preferably 100 gf to800 gf. When the three-point bending value of the inner shaft 210 is 100gf or less, the inner shaft 210 hangs down, does not form a spiral, andwhen the three-point bending value of the inner shaft 210 exceeds 800gf, the inner shaft does not drip in a rolled state, so it does notbecome a three-dimensional helical structure. When the three-pointbending value of the inner shaft 210 is 300 gf to 700 gf, when the innershaft 210 is inserted into a lumen of the outer shaft 110 which is not athree-dimensional helical structure as a single body, the inner shaft210 is three-dimensionally shape, which is preferable because the innershaft 210 has a spiral shape. In accordance with an embodiment, thethree-point bending value of the inner shaft 210 may be determined by aflexural modulus measured by the same method, and the three-pointbending value is preferably 30 MPa to 280 MPa, and more preferably 100MPa to 250 MPa.

The inner shaft 210 is insertable into the lumens 110 a and 121 a of theouter catheter 100. In general, as the length of the catheter in thelongitudinal direction is longer, a pushing force of the surgeon on theproximal end side is less likely to be transmitted to the distal endside. In the catheter assembly 10 according to the present embodiment,the surgeon delivers the catheter assembly 10 to a target site in theblood vessel while the inner catheter 200 is inserted into the outercatheter 100. When the surgeon pushes the catheter assembly 10, theinner catheter 200 supports the outer catheter 100 from the inner side,so that the pushing force of the surgeon on the proximal side is easilytransmitted to the distal end side. Thus, the surgeon can relativelyeasily deliver the catheter assembly 10 to the target site of the lowerlimb via the artery of the arm.

A part A of the inner shaft 210 (see FIG. 1, hereinafter referred to asa “wound portion A”) forms a wound first shape in a state where theinner shaft 210 is suspended in a gravity direction G by holding the hub220 as illustrated in FIG. 3A.

The “state where the inner shaft 210 is suspended in the gravitydirection G by holding the hub 220” can be formed, for example, byholding the hub 220 with a holding tool F fixed to the ceiling andcausing the inner shaft 210 to be suspended in the gravity direction G.In FIG. 3A, the holding tool F is constituted by a hook F1 fixed to theceiling and a cord F2 hooked by the hook F1 and wound around theproximal end side of the hub 220, but the configuration of the holdingtool F is not particularly limited as long as the holding tool can holdthe hub 220.

The first shape is not particularly limited as long as the shaft iswound and a length L3 of the inner shaft 210 along the gravity directionG (see FIG. 3A) is longer than a length L4 (see FIG. 5) of the innershaft 210 along the gravity direction G in a placed state to bedescribed later. Thus, examples of the first shape include athree-dimensional helix and a shape having both a three-dimensionalhelix and a two-dimensional spiral, and the like, but do not include a“C shape” in which a central portion of the inner shaft 210 is just bentwhen the inner shaft 210 in the suspended state is viewed in a frontview, a “J shape” in which the distal end portion of the inner shaft 210is just curved, a shape with the “only two-dimensional spiral”, and thelike. In the present embodiment, the first shape is a three-dimensionalhelix formed around an axis X1 along the gravity direction asillustrated in FIG. 3A. In the present embodiment, the wound portion Ain the first shape is in the state of being wound around the axis X1 byabout two and one quarter turns in which portions (for example, C1 andC2) adjacent to each other in the direction of the axis X1 are separatedfrom each other in the direction of the axis X1. In the presentembodiment, the axis X1 of the helix extends along the gravity directionG, but does not need to extend along the gravity direction G, and may beinclined with respect to the gravity direction G.

In this manner, the wound portion A forms the first shape in thesuspended state. In addition, the catheter assembly 10 forms a woundthird shape in which the outer catheter 100 not having the wound shapeand the inner catheter 200 having the first shape are combined in astate where the inner catheter 200 is inserted into the outer catheter100, and the outer shaft 110 and the inner shaft 210 are suspended byholding the hub 220 as illustrated in FIG. 3B. Thus, for example, whenthe surgeon holds and manipulates the proximal end side of the innercatheter 200 or the catheter assembly 10, the inner catheter 200 or thecatheter assembly 10 forms the wound shape and becomes compact in thegravity direction G without being wound by the surgeon. Thus, the innercatheter 200 and the catheter assembly 10 can help reduce the risk ofbeing in contact with an unclean surface such as a floor, and it becomesunnecessary or rather easy for the surgeon to perform work of bundlingthe inner catheter 200 and the catheter assembly 10 with a clip or thelike so as to prevent the catheter 200 from coming into contact with theunclean surface such as the floor. Although the third shape formed bythe catheter assembly 10 is the three-dimensional helix, wound around anaxis X2 along the gravity direction G with the number of turns reducedas compared with the first shape of the inner shaft 210 in the presentembodiment, the third shape is not particularly limited as long as thethird shape is the wound shape. For example, the axis X2 may be inclinedwith respect to the gravity direction G.

In the state where the inner shaft 210 is suspended, at least a part ofthe inner shaft 210 may form the first shape, and it is preferable thata half or more of the distance from the distal end of the inner shaft210 to the distal end of the hub 220 forms the first shape. The wider aregion of the inner shaft 210 forming the first shape becomes, the morecompact the inner shaft 210 becomes in the gravity direction G. In thepresent embodiment, the wound portion A is a portion excluding thedistal end portion of the inner shaft 210 and the vicinity of the distalend of the hub 220 as illustrated in FIG. 1. A range of the distal endportion is not particularly limited, but can be set, for example, to arange of about from 0 mm to 400 mm, and preferably about from 0 mm to150 mm, from the most distal end to the proximal end side. A range ofthe vicinity of the most distal end of the hub 220 is not particularlylimited, but can be set, for example, to a range of about from 0 mm to400 mm, and preferably about from 0 mm to 150 mm, from the most distalend to the distal end side of the hub 220.

The inner shaft 210 is not particularly limited, but can be set suchthat a maximum length (a maximum outer diameter R of the helix) in adirection perpendicular to the gravity direction G is equal to or longerthan 1/10 and equal to or smaller than ⅓ of a length L2 (hereinaftersimply referred to as the “length L2 of the inner shaft 210”, seeFIG. 1) from the distal end of the inner shaft 210 to the distal end ofthe hub 220 in the straight state as illustrated in FIG. 3A. When themaximum outer diameter R of the helix is set, for example, to be equalto or longer than 1/10 of the length L2 of the inner shaft 210 asdescribed above, the inner shaft 210 becomes more compact in the gravitydirection G in the suspended state. In addition, when the maximum outerdiameter R of the helix is set, for example, to be equal to or smallerthan ⅓ of the length L2 of the inner shaft 210 as described above, it ispossible to suitably impart a curl to the inner shaft 210 to form thefirst shape.

A length L3 (helical length L3 of the inner shaft 210, see FIG. 3A)along the gravity direction G of a portion of the inner shaft 210exposed from the hub 220 in the suspended state is not particularlylimited, but is preferably equal to or smaller than ⅔ of the length L2of the inner shaft 210, for example. Further, the helical length L3 ofthe inner shaft 210 is not particularly limited, but can be 30% to 50%of the length L2 of the inner shaft 210, for example. When the helicallength L3 of the inner shaft 210 is set in this manner, the inner shaft210 becomes even more compact in the gravity direction G.

As illustrated in FIGS. 4A and 5, the wound portion A is wound and formsa second shape in which the length L4 of the inner shaft 210 along thegravity direction G is shorter than the length L3 of the inner shaft 210along the gravity direction G in the first shape in a state where theinner catheter 200 is placed on a flat reference plane T perpendicularto the gravity direction G.

As illustrated in FIG. 5, the “state of being placed on the referenceplane T” means a state where the inner catheter 200 is placed on thereference plane T and the inner catheter 200 is in contact with no partother than the reference plane T. That is, an external force does notact on the inner catheter 200 except for gravity and a force caused bythe contact with the reference plane T (a frictional force against thereference plane T and a resistance from reference plane T) in thisstate. In this manner, the wound portion A forms the second shape in theplaced state without being wound by the surgeon. In addition, thecatheter assembly 10 also forms a fourth shape in which the outer shaft110 and a part of the inner shaft 210 are wound with the smaller numberof turns than the second shape by combining the outer catheter 100without the wound shape and the inner catheter 200 with the second shapein the placed state as illustrated in FIG. 4B. Before inserting thecatheter assembly 10 into the blood vessel of the patient, the surgeonfills a medical tray or the like with a priming solution, and performspriming work of immersing the inner catheter 200 and the catheterassembly 10 in the priming solution. In addition, there is a case wherethe inner catheter 200 or the catheter assembly 10 is temporarily placedon a table, the medical tray, or the like during a procedure. In such acase, the inner catheter 200 or the catheter assembly 10 forms a woundshape on the table or the medical tray without being wound by thesurgeon, and becomes compact in the gravity direction G. In this manner,the surgeon does not need to wind the inner catheter 200 or the catheterassembly 10 such that the inner catheter 200 or the catheter assembly 10does not become a hindrance or fits in the medical tray.

The second shape is not particularly limited as long as the catheter iswound and the length L4 (see FIG. 5) of the inner shaft 210 along thegravity direction G is shorter than the length L3 (see FIG. 3A) of theinner shaft 210 along the gravity direction G in the suspended state.Thus, examples of the first shape include a “two-dimensional spiral”, an“a shape” of being wound by one turn when the reference plane T isviewed from above, and a “C shape” of being bent so as to surround theaxis X1 when the reference plane T is viewed from above, and the like.

In the present embodiment, the second shape is a shape obtained bywinding the catheter around the axis X1 about two and a quarter turnswhen the reference plane T is viewed from above as illustrated in FIG.4A. In addition, in the second shape, the inner shaft 210 hasoverlapping portions B1 and B2 in which wound portions C3 and C4 overlapeach other when the reference plane T is viewed from above. Asillustrated in FIG. 5, the wound portions C3 and C4 abut on each otherin the overlapping portions B1 and B2 (although only the overlappingportion B1 is illustrated in the drawing). In this manner, since theadjacent portions C3 and C4 abut on each other in the overlappingportions B1 and B2, the inner catheter 200 becomes even more compact inthe gravity direction G. Incidentally, the inner catheter 200 may beconfigured such that the length L4 of the inner shaft 210 along thegravity direction G in the placed state is shorter than the length L3(see FIG. 3A) along the gravity direction G of the inner shaft 210 inthe suspended state, and the adjacent portions C3 and C4 may be slightlyseparated from each other without abutting on each other.

Although a method of imparting the curl to the inner shaft 210 to formthe first shape and the second shape is not particularly limited, it ispossible to use, for example, a method of winding the inner shaft 210along an annular jig or a columnar jig and maintaining the state for apredetermined time, or the like. Incidentally, when the inner shaft 210is inserted into the outer shaft 110 to which no curl is imparted, it ispreferable that the catheter assembly 10 has a strong curl (shaperetention property) to the extent that a wound shape (theabove-described third or fourth shape) can be formed in the suspendedstate or placed state while being loosened due to the shape of the outershaft 110 to which no curl is imparted.

The inner shaft 210 is preferably made of a resin material. When theinner shaft 210 is made of the resin material, it is possible tosuitably impart the curl to the inner shaft 210 by the above-describedmethod. Although the resin material forming the inner shaft 210 is notparticularly limited, it is possible to use, for example, the same resinmaterial as the outer layer 113 of the outer catheter 100 describedabove. In addition, the inner shaft 210 may have a hydrophilic coatinglayer on an outer surface on the distal end side of the inner shaft 210.

Incidentally, the inner shaft 210 may have a marker (not illustrated)having X-ray contrast property at a distal end portion of the innershaft 210.

The length L2 of the inner shaft 210 can be set to be longer than thelength L1 of the outer shaft 110. With this configuration, the distalend portion of the inner shaft 210 can be exposed from a distal endopening of the outer shaft 110 in the state of being inserted into theouter shaft 110 (see FIG. 6).

Next, the hub 220 will be described.

As illustrated in FIG. 1, the hub 220 has a hollow inner hub bodyportion 221 and a helical groove 222 provided on an inner surface of theinner hub body portion 221. The inner hub body portion 221 has a lumen221 a formed over the entire length of the inner hub body portion 221.The lumen 221 a communicates with the lumen 210 a of the inner shaft210.

The hub 220 material is not particularly limited, for example, the samematerial as the hub 120 of the outer catheter 100 can be used.

Use Example

Next, a description will be given regarding a use example of thecatheter assembly 10 in which the catheter assembly 10 is applied to aprocedure for treating a lesion (stenosis N) generated in a leftsuperficial femoral artery (SFA) R7 of a lower limb via a radial arteryR1 of a right arm of a patient with reference to FIG. 6. The catheterassembly 10 can be evaluated with a three-point bending value obtainedby the same method as the outer shaft 110 and the inner shaft 210. Inthe case of an outer diameter of 2.4 mm and an inner diameter of 1.1 mm,the three-point bending value of the catheter assembly 10 is 150 gf to1000 gf, more preferably 300 gf to 800 gf, more preferably 350 gf to 650gf. If the three-point bending value of the catheter assembly 10 is 150gf or less, the catheter assembly 10 hangs down and does not form ahelix, and when the three-point bending value of the catheter assembly10 exceeds 1000 gf, the catheter assembly 10 does not drip in a rolledstate and does not have a three-dimensional helical structure. When thethree-point bending value of the catheter assembly 10 is 300 gf to 700gf, when the inner shaft 210 is inserted into a lumen of the outer shaft110 which is not a three-dimensional helical structure as a single body,the inner shaft 210 is three-dimensionally it is preferable because ithas a spiral shape. Alternatively, it may be determined by the flexuralmodulus measured by the same method, and it is preferable that theapparent flexural modulus when the outer diameter is 2.4 mm and theinner diameter is 1.1 mm is preferably 40 MPa to 320 MPa, morepreferably 90 MPa to 250 MPa, and most preferably 100 MPa to 210 MPa.

First, the surgeon places the outer catheter 100 and the inner catheter200 on a medical tray, and performs the priming work of immerging theouter catheter 100 and the inner catheter 200 in the priming solution.

Next, the surgeon inserts the inner catheter 200 into the outer catheter100 and screws the protrusion 124 of the outer catheter 100 into thehelical groove 222 of the inner catheter. As a result, when the catheterassembly 10 is inserted into the blood vessel of the patient, thesurgeon can integrally operate the outer catheter 100 and the innercatheter 200, thereby facilitating the operation. The surgeon cantemporarily place the assembled catheter assembly 10 on the medical trayor the like until the catheter assembly 10 is used again.

Next, the surgeon punctures the radial artery R1 of the right arm withthe introducer sheath S and causes the introducer sheath S to remain inthe radial artery R1 as illustrated in FIG. 6. As a result, the surgeoncan secure an introduction path for introducing the catheter assembly 10into the radial artery R1.

Next, the surgeon inserts the catheter assembly 10 into the introducersheath S in a state where the guide wire GW has been inserted into thelumen of the catheter assembly 10. Then, the surgeon introduces thecatheter assembly 10 into the radial artery R1 along the guide wire GW.

Next, the surgeon pushes the catheter assembly 10 to proceed along thepreceding guide wire GW to a target site (for example, the vicinity ofthe upper part of the left superficial femoral artery (SFA) R7) in frontof the stenosis N. Since the catheter assembly 10 has the wound shape,the surgeon can easily move the catheter assembly 10 to proceed along acurved artery such as a right subclavian artery R2, a brachiocephalicartery R3, and an aortic arch R4, or the like. In addition, the surgeoncan push the catheter assembly 10 forward such that the outer catheter100 draws a helix while abutting on wall surfaces of a thoracic aorta R5and an abdominal aorta R6 since the catheter assembly 10 has the woundshape.

Next, after the distal end of the catheter assembly 10 reaches thetarget site, the surgeon releases the screwing between the helicalgroove 222 of the inner catheter 200 and the protrusion 124 of the outercatheter 100. Then, the surgeon removes the inner catheter 200 out ofthe body while leaving the outer catheter 100 and the guide wire GW inthe blood vessel.

Next, the surgeon inserts a balloon catheter (not illustrated) having anexpanded portion, which is expandable and contractible, at a distal endof the balloon catheter into the lumens 110 a and 121 a of the outercatheter 100 along the guide wire GW. Further, the surgeon pushes theballoon catheter into the lumens 110 a and 121 a of the outer catheter100 such that the expanded portion protrudes from the distal end of theouter catheter 100 and the expanded portion is arranged at the stenosisN. Incidentally, since the catheter assembly 10 abuts on the wallsurfaces of the thoracic aorta R5 and the abdominal aorta R6 whiledrawing the helix as described above, a contact area between the outercatheter 100 and a blood vessel wall is wide. Thus, even if a reactionforce caused by pushing the balloon catheter forward is transmitted tothe outer catheter 100, it is possible to suitably suppress the movementof the outer catheter in a direction of being removed out of the bodydue to a frictional force between the outer catheter 100 and each wallsurface of the thoracic aorta R5 and the abdominal aorta R6.

Next, the surgeon expands the expanded portion of the balloon catheterto push and dilate the stenosis N. Next, the surgeon contracts theexpanded portion of the balloon catheter and removes the ballooncatheter and the guide wire GW out of the body.

Next, the surgeon removes the outer catheter 100 out of the body. Next,the surgeon removes the introducer sheath S out of the body and stopsbleeding of a puncture site.

Although the use example of the catheter assembly 10 has been describedabove, the procedure to which the catheter assembly 10 is applied is notlimited to the above-described procedure. For example, a site to bepierced is not limited to the radial artery R1 of the right arm, but maybe a radial artery of a left arm, for example. In addition, the lesionis not limited to one generated in the left superficial femoral arteryR7, but may be those generated in, for example, a right superficialfemoral artery, right and left iliac arteries, and right and leftpopliteal arteries. In addition, the treatment to be performed via theouter catheter 100 is not limited to the treatment using only theballoon catheter. For example, a stent may be arranged on an outersurface of a balloon. In addition, a long object such as a catheterother than the balloon catheter, an endoscope, an ultrasonic probe, anda temperature sensor may be inserted or removed via the outer catheter100, and various liquids such as a contrast agent (X-ray contrastagent), a medical solution, and saline may be injected.

The above-described inner catheter 200 according to the presentembodiment includes the elongated inner shaft 210 to be inserted intothe blood vessel and the hub 220 to be connected to the proximal endside of the inner shaft 210. The inner shaft 210 forms the first shapein which at least the part A of the inner shaft 210 is wound in thestate where the inner shaft 210 is suspended in the gravity direction Gby holding the hub 220. In the state where the hub 220 and the innershaft 210 are placed on the flat reference plane T perpendicular to thegravity direction G, the inner shaft 210 forms the second shape in whichat least the part A of the inner shaft 210 is wound and the length L4 ofthe inner shaft 210 along the gravity direction G is shorter than thelength L3 along the gravity direction G of the inner shaft 210 in thefirst shape.

According to the inner catheter 200 configured as described above, whenthe surgeon holds and manipulates the proximal end side of the innercatheter 200, at least the part A of the inner shaft 210 is wound toform the first shape and becomes compact. Thus, the risk of the innercatheter 200 being in contact with an unclean surface such as a floor isreduced, and it becomes unnecessary or rather easy for the surgeon toperform work of bundling the inner catheter 200 with a clip or the likeso as to prevent the contact with the unclean surface such as the floor.In addition, when the surgeon places the inner catheter 200 on a medicaltray, a table, or the like, at least the part A of the inner shaft 210forms the second shape and becomes more compact than the first shape. Inthis manner, it is possible to provide the inner catheter 200 which israther easy to handle.

In addition, the first shape is the three-dimensional helix. Thus, theinner shaft 210 becomes compact in the gravity direction G in thesuspended state.

In addition, the second shape has the overlapping portions B1 and B2 inwhich the wound portions C3 and C4 of the inner shaft 210 overlap eachother when the reference plane T is viewed from above. In theoverlapping portions B1 and B2, the wound portions C3 and C4 abut oneach other. Thus, when the surgeon has placed the inner catheter 200 onthe medical tray, the table, or the like, the inner shaft 210 becomescompact.

In addition, in the state where the hub 220 is held and the inner shaft210 is suspended, a portion, which is a half or more of the inner shaft210 from the distal end of the inner shaft 210 to the distal end of thehub 220 forms the first shape, and a maximum length R of the inner shaft210 in the direction perpendicular to the gravity direction G in thefirst shape is equal to or longer than 1/10 and equal to or smaller than⅓ of the length L2 from the distal end of the inner shaft 210 to thedistal end of the hub 220 in the straight state. When being set asdescribed above, the inner shaft 210 becomes even more compact in thegravity direction G, and it is also possible to suitably impart the curlto the inner shaft 210 to form the first shape.

In addition, the length L3 of the portion of the inner shaft 210 exposedfrom the hub 220 along the gravity direction G in the first shape isequal to or smaller than ⅔ of the length L2 of the inner shaft 210 fromthe distal end of the inner shaft 210 to the distal end of the hub 220in the straight state. When being set as described above, the innershaft 210 becomes even more compact in the gravity direction G.

In addition, the catheter assembly 10 according to the presentembodiment includes the outer catheter 100 and the inner catheter 200that is insertable into the outer catheter 100. The outer catheter 100and inner catheter 200 include the elongated shafts 110 and 210 and thehubs 120 and 220 connected to the shafts 110 and 210, respectively. Theinner shaft 210 of the inner catheter 200 forms the first shape in whichat least the part A of the inner shaft 210 is wound in the state wherethe inner shaft 210 is suspended in the gravity direction G by holdingthe hub 220. The third shape is formed in which a part of the shafts ofthe outer catheter 100 and the inner catheter 200 is wound in the statewhere the inner catheter 200 is inserted into the outer catheter 100,and the shafts 110 and 210 of the outer catheter 100 and the innercatheter 200 are suspended in the gravity direction G by holding the hub220 of the inner catheter 200.

According to the catheter assembly 10 configured as described above,when the surgeon holds and manipulates the proximal end side of thecatheter assembly in the state where the inner catheter is inserted intothe outer catheter, at least a part of the shaft of the catheterassembly is wound to form the third shape and becomes compact. Thus, therisk of the catheter assembly being in contact with an unclean surfacesuch as a floor is reduced, and it becomes unnecessary or easy for thesurgeon to perform work of bundling the catheter with a clip or the likeso as to prevent the contact with the unclean surface such as the floor.In this manner, it is possible to provide the catheter assembly which isrelatively easy to handle.

Modified Example

FIG. 7 is a view illustrating an inner shaft 310 according to a modifiedexample. Hereinafter, the inner shaft 310 according to the modifiedexample will be described.

The inner shaft 310 according to the modified example is different fromthat of the above embodiment in terms of a shape (second shape) in astate of being placed on the reference plane T. Since the otherconfigurations are the same as those in the above embodiment, thedescription of the other configurations will be omitted.

A second shape of the inner shaft 310 is a two-dimensional spiral. Inthis manner, the second shape is wound on the reference plane T (thatis, wound on a two-dimensional plane) without having an overlappingportion in which wound portions of the inner shaft 310 overlap eachother when the reference plane T is viewed from above.

Thus, the inner shaft 210 becomes even more compact in the gravitydirection G as compared with the inner shaft 210 according to the aboveembodiment.

Although the catheter and the catheter assembly according to the presentinvention have been described through the embodiments as above, thepresent invention is not limited to only the configurations that havebeen described in the specification but can be appropriately changedbased on the description of the claims.

For example, the above embodiment has been described by exemplifying theinner catheter of the guiding catheter as the catheter to which thepresent invention is applied. However, the invention is not limitedthereto, and can be applied to, for example, an introducer sheath, adilator, a guiding sheath, a angiographic catheter, a medical solutionadministration catheter, and the like.

In addition, the above embodiment has been described by exemplifying theguiding catheter having a dual structure that includes the outercatheter and the inner catheter as the catheter assembly to which thepresent invention is applied. However, the invention is not limited tothe above embodiments, and can be applied to, for example, an introducerincluding an introducer sheath (corresponding to the “outer catheter”)and a dilator (corresponding to the “inner catheter”).

In addition, the mode in which the inner catheter forms the first shapeand the second shape has been described in the above embodiment, but theinner catheter does not necessarily form the first shape and the secondshape and the outer catheter may form the first shape and the secondshape, or both the inner catheter and the outer catheter may form thefirst shape and the second shape.

The detailed description above describes a catheter and a catheterassembly. The invention is not limited, however, to the preciseembodiments and variations described. Various changes, modifications andequivalents can be effected by one skilled in the art without departingfrom the spirit and scope of the invention as defined in theaccompanying claims. It is expressly intended that all such changes,modifications and equivalents which fall within the scope of the claimsare embraced by the claims.

What is claimed is:
 1. A treatment method comprising: preparing acatheter assembly by inserting an inner catheter into an outer catheterand screwing a protrusion of the outer catheter into a helical groove ofthe inner catheter; inserting a guide wire into a lumen of the innercatheter of the catheter assembly such that the guide wire protrudesfrom a distal end of the inner catheter; inserting the catheter assemblyinto an introducer sheath, the introducer sheath configured to piercethrough and remain in a radial artery of a living body, in a state wherethe guide wire is inserted into a lumen of the catheter assembly;introducing the catheter assembly into the radial artery along the guidewire; pushing the catheter assembly along the guide wire to a targetsite in front of a stenosis of a blood vessel; releasing the screwingbetween the helical groove of the inner catheter and the protrusion ofthe outer catheter after a distal end of the catheter assembly reachesthe target site; removing the inner catheter from the living body whileleaving the outer catheter and the guide wire in the blood vessel;inserting a treatment device along the guide wire into a lumen of theouter catheter; and causing the outer catheter to abut on at least apart of wall surfaces of a thoracic aorta and an abdominal aorta whiledrawing a helix and causing the treatment device to protrude from adistal end of the outer catheter such that an expanded portion isarranged at the stenosis.
 2. The method according to claim 1, whereinthe inner catheter is a flexible tubular member configured to fit withinthe outer catheter, the inner catheter having a lumen extending from aproximal end of the inner catheter to a distal end of the innercatheter; and the outer catheter includes a tubular inner layer, areinforcing member provided on an outer circumferential surface of thetubular inner layer, and an outer layer surrounding the tubular innerlayer and the reinforcing member.
 3. The method according to claim 1,further comprising: applying a hydrophilic coating on one or more of anouter surface of the outer layer of the outer catheter and an outersurface of the inner catheter.
 4. The method according to claim 1,further comprising: immerging the inner catheter and the outer catheterin a priming solution prior to preparing the catheter assembly byinserting the inner catheter into the outer catheter.
 5. The methodaccording to claim 1, further comprising: moving the catheter assemblyalong a curved artery to the target site, the curved artery being aright subclavian artery, a brachiocephalic artery, or an aortic arch. 6.The method according to claim 1, wherein the target site is in an iliacartery, a femoral artery, or a popliteal artery, the inner shaft havinga length of 1300 mm to 1500 mm to reach the iliac artery, a length of1500 mm to 1700 mm to reach the femoral artery, or a length of 1700 mmto 1900 mm to reach the popliteal artery.
 7. The method according toclaim 1, further comprising: transmitting a reaction force to the outercatheter with the pushing of the treatment device forward along theguide wire; and suppressing a movement of the outer catheter in adirection of being removed out of the living body caused by the reactionforce by a frictional force between the outer catheter and each wallsurface of the thoracic aorta and the abdominal aorta.
 8. The methodaccording to claim 1, wherein the treatment device is a ballooncatheter, the method comprising: expanding an expanded portion of theballoon catheter to dilate the stenosis.
 9. The method according toclaim 9, further comprising: contracting the expanded portion of theballoon catheter; and removing the balloon catheter and the guide wirefrom the living body.
 10. The method according to claim 9, furthercomprising: removing the outer catheter from the living; removing theintroducer sheath from the living body; and stopping a bleeding of apuncture site in the radial artery of the living body.
 11. The methodaccording to claim 1, wherein the inner catheter includes an elongatedinner shaft and a hub, the hub being connected to a proximal end of theinner shaft, the method further comprising: winding at least a part ofthe inner shaft to form a first shape in a state where the inner shaftis suspended in a gravity direction by holding the hub.
 12. The methodaccording to claim 11, further comprising: placing the hub and the innershaft in a state where on a flat reference plane perpendicular to thegravity direction; and forming the inner shaft in a second shape inwhich at least the part of the inner shaft is wound and a length of theinner shaft along the gravity direction is shorter than a length alongthe gravity direction of the inner shaft in the first shape.
 13. Themethod according to claim 12, wherein the flat reference planeperpendicular to the gravity direction is a medical tray or a table. 14.The method according to claim 11, wherein the first shape is athree-dimensional helix.
 15. The method according to claim 11, wherein aportion, which is a half or more of the inner shaft from a distal end ofthe inner shaft to a distal end of the hub forms the first shape in astate where the inner shaft is suspended; and a maximum length of theinner shaft in a direction perpendicular to the gravity direction in thefirst shape is equal to or longer than 1/10 and equal to or smaller than⅓ of a length from the distal end of the inner shaft to the distal endof the hub in a straight state.
 16. The method according to claim 11,wherein a length of a portion of the inner shaft exposed from the hubalong the gravity direction in the first shape is equal to or smallerthan ⅔ of the length of the inner shaft from the distal end of the innershaft to the distal end of the hub in the straight state.
 17. Atreatment method comprising: inserting an inner catheter into an outercatheter and screwing a protrusion of the outer catheter into a helicalgroove of the inner catheter to form a catheter assembly; inserting aguide wire into a lumen of the inner catheter and protruding the guidewire from a distal end of the inner catheter; puncturing a radial arteryof a living body with an introducer sheath; inserting a guide wire intoa lumen of the catheter assembly; introducing the catheter assemblyalong with the guide wire into the radial artery via the introducersheath; pushing the catheter assembly along the guide wire to a targetsite in a blood vessel; releasing the screwing between the helicalgroove of the inner catheter and the protrusion of the outer catheterafter a distal end of the catheter assembly reaches the target site;removing the inner catheter from the living body while leaving the outercatheter and the guide wire in the blood vessel; inserting a treatmentdevice along the guide wire into a lumen of the outer catheter; andcausing the outer catheter to abut on at least a part of wall surfacesof a thoracic aorta and an abdominal aorta while drawing a helix andcausing the treatment device to protrude from a distal end of the outercatheter at the target site.
 18. The method according to claim 17,wherein the inner catheter is a flexible tubular member configured tofit within the outer catheter, the inner catheter having a lumenextending from a proximal end of the inner catheter to a distal end ofthe inner catheter; and the outer catheter includes a tubular innerlayer, a reinforcing member provided on an outer circumferential surfaceof the tubular inner layer, and an outer layer surrounding the tubularinner layer and the reinforcing member.
 19. The method according toclaim 17, further comprising: applying a hydrophilic coating on one ormore of an outer surface of the outer layer of the outer catheter and anouter surface of the inner catheter.
 20. The method according to claim17, wherein a portion, which is a half or more of the inner shaft from adistal end of the inner shaft to a distal end of the hub forms the firstshape in a state where the inner shaft is suspended; and a maximumlength of the inner shaft in a direction perpendicular to the gravitydirection in the first shape is equal to or longer than 1/10 and equalto or smaller than ⅓ of a length from the distal end of the inner shaftto the distal end of the hub in a straight state.